The present simple tense can be used to talk about things that are generally true or happen regularly.

Positive: subject + infinitive
Negative: subject + do/does + not + infinitive
Question: Do/Does + subject + infinitive

Note: In positive sentences when the subject is he/she/it, we add s/es/ies to the infinitive form of the verb.
For example;

• She plays football every weekend.
• It catches fire easily.
• He studies before every exam.

Common uses:

1. To talk about habits and routines

• I brush my teeth twice a day.
• I do not smoke.
• Do they study at the library?

2. To talk about general truths and facts

• The Earth revolves around the sun.
• Cats do not like water.
• Does gravity exist on the moon?

3. To talk about scheduled events in the future

• The train leaves at 9 am tomorrow.
• They do not have a meeting next week.
• Does he have a flight tomorrow morning?